Solar H-alpha

(all photos by John Mahony, except the last)

This photo shows a sunspot region with some prominences on the
horizon.
Note the bright areas around the spots. Because of this the sun
is
in fact usually slightly brighter overall when there are many
sunspots.
Prominences generally follow magnetic field lines that extend above the
surface, which accounts for the arches and bridges frequently seen.

These photos show more prominences. This material can leave
the
surface, as in the second and sixth pictures. Large outbursts,
known
as flares or coronal mass ejections, can fling material to the earth,
causing
auroras
when the material interacts with the earth's upper atmosphere.

This image was taken with a CCD camera, which captures a very wide
range
of brightness. So much so, in fact, that I had to process
different
parts differently to get it to show well on a computer monitor.
At
the very center is a dark sunspot and its surrounding dark
penumbra.
This was processed lighter than the surrounding area or it would have
been
just one big black spot. The rest of the center vertical strip
shows
the turbulent region surrounding the spot. The surrounding strips
show normal solar surface with a "rice grain" texture of light and dark
regions- each "grain" is a convection cell. The right strip of
these
two was processed lighter since it is near the edge of the sun, which
normally
appears darker than the rest of the sun. The far right strip was
processed even lighter to show the thin "atmosphere" layer at the
surface.
The inset in the right strip was processed brighter yet to show a
prominence.
It appears detached from the surface, but this is due only to the great
difference in processing. In fact, all parts of this image are
positioned
exactly as in the original single image.

Here's the same image, processed more evenly, with color added in
Photoshop.

Prominences form in long ridges. Seen against the surface, they
form dark snake-like features.

This image was taken by Buck
Harley, using a Baader
white-light filter on his 7" refractor, which he later donated to PGO.